Dr. Clarke did the country a service last year, by publishing his little volume entitled "Sex in Education," in which he called attention to some physiological points in the school-experience of girls, in such a way as to provoke half a score of replies, and to bring the subject very effectually before the public. He took ground against co-education, or the subjection of girls to the same conditions of study as boys, and showed how that system works serious and extensive injuries to the female constitution. The little volume now issued, while it is not a formal reply to his critics, pursues the subject of the physiological basis of education. Instead of dealing with mind as an abstraction, he takes up the brain in which it is embodied, and shows how mental development is, at bottom, really a process of "brain-building." Metaphysical vagueness is here escaped, and we have to deal with tangible and definite results that are dependent upon established laws. The body is thus brought into account, and we see how education, or mental development, is so deeply complicated with physiological conditions, that these can never be neglected in the intelligent consideration of mental culture.

At the close of this special essay, Dr. Clarke appends a mass of valuable testimony in regard to the practical workings of the system of co-education. The short article in our preceding pages, which we have entitled "Educated to Death," is taken from this portion of Dr. Clarke's book. By direction of the State Board of Health of Massachusetts, Dr. F. Winsor, of Winchester, collected some valuable statistics on "School Hygiene," and the effects of co-education formed one feature of the investigation. Circulars were sent to physicians, teachers, and others in the State, soliciting information in answer to questions. Replies were received from one hundred and sixty persons, of whom one hundred and fifteen are stated to be physicians; nineteen, physicians and members of school committees; fourteen, teachers of experience, and six, superintendents of schools. The Board requested that all the replies should be "based on personal observation." The question, "Is one sex more liable than the other to suffer in health from attendance on school?" was answered substantially as follows:

Females more liable than males, by

109

Males more liable than females, by

1

Both alike liable, by

81

Neither is in danger, by

4

Not in district schools, by

1

Not if both sexes exercise alike in the open air, by

1

Unable to answer, by

5

To the question, "Does the advent of puberty increase this liability?" the answers came:

Yes, by

120

No, by

12

Uncertain, by

9

Many of the correspondents accompanied their replies with comments which were mostly in the following strain:

"The female scholars are more susceptible to emotional influences, and if there be stimuli in school, appealing to pride and vanity, they are so emulous as to injure themselves."

Again: "This baleful result becomes very strikingly manifested as the girls approach the age of puberty. Under the abnormal conditions of the physical system produced by this cause, not only do the more emulous and studious girls suffer from the study which they evidently ought to intermit, but the ordinary and habitual task-work necessary to keep abreast of the studies is far too severe a draught on many constitutions."

Again: "This greater liability in the female is an established fact; and our State and local School Boards should at once take steps to modify our system of education in accordance with the fact, however great may be the change required."

From various communications received by Dr. Clarke with reference to the workings of co-education, we extract the following from that of D. H. Cochran, LL. D., the distinguished head of the Brooklyn Collegiate and Polytechnic Institute, who had ten years' experience of co-education in the

New York State Normal School. Dr. Cochran says it had been observed that a large number of students who left the institution were unfitted for teaching by impaired health, so that Dr. Woolworth made an appeal to the commissioners "to send only such students to the school as possessed a sound physical organization. . . .

"Notwithstanding his earnest efforts, the evils of failing health on the part of our female pupils continued, and the consequent incapacity to discharge the duties for which the State was educating them. But the facts were hardly suspected until suggested accidentally, in 1866, and then the reports of Dr. Bailey, who had been consulted by a large number of the female pupils, and of a lady in the faculty of the school, revealed the astounding fact that, among about one hundred and eighty female pupils then in the school, there were over twenty cases in which the periodical functions peculiar to the sex had ceased for over two months, and that there was a much larger number of similar cases, less serious. Even then, the causes were attributed to stairs, bad ventilation, and recklessness of health, without suspicion that the evils were inherent in a system which imposed upon the female continuous labor, and in amount equal to that of the male, who was in many, and perhaps in the majority of cases, her intellectual inferior, but who was the inheritor of continuously rugged health. . . .

"The logic of facts, to which our eyes were so slowly, and I fear unwillingly, opened, finally led to a more elastic course, optional to the females. But, while this gave relief to a part of the pupils, it augmented the evils to others; for the more ambitious regarded the exemption from advanced mathematics as a reflection upon their intellectual ability, and persisted in taking the severer course in spite of the advice of their teachers. . . .

"This spirit was indicated in the remark of one of these pupils to a lady-teacher who was advising her to drop the mathematics of the senior year, on account of failing health. She said, 'I will do it, if it kills me.' We can hardly wonder that the teacher impatiently replied: 'If it killed you, perhaps it would not so much matter; but are you quite willing to impose upon your friends the burden of your lifelong helplessness?'

"I urge the separate higher education of females solely upon physical grounds. My experience has forced me to this. I have a record of my former pupils who stood high in their classes, who did their work with seeming ease, but who have been unable to teach, and now confess that they date the beginning of their present sufferings to the continuous labor of school. I have in my mind, as I write, the case of a young lady from Tioga County, now residing in this city, who stood foremost in her class, and without apparent effort, but who has never been in sound health since her graduation; and she attributes her present condition to the insensible exhaustion of her class-work. Yet she would have been the very last to confess overwork while a pupil; and I do not think that either she, or her teachers, then suspected it."

(Practical Astronomy and the Observatories of Europe and America, from the Middle of the Seventeenth Century until the Present Time. By André and Rayet, Assistant Astronomers in the Paris Observatory. Part I.—England.)

This is the first of a series of three volumes to be published for the joint authors, who are both skillful and able astronomers, known in the scientific world by various important researches. This volume treats of the observatories of England alone, and it is to be followed by two others treating of those of Scotland, Ireland, the Continent, and America.

The design of the work is most excellent, and its execution is thoroughly good, as indeed might have been anticipated. In brief, the plan of the authors has been to give a short history of each of the many institutions devoted to practical astronomy, with a sketch of the life and works of each of the directors who has been in charge of it, as well as an account of the principal instruments and the uses to which they have been devoted.

Quite a number of very good woodcuts are supplied, which give perspective views of some of the most important instruments, and these alone lend great value to the book. Many of these cuts are derived from engravings given in the publications of the various observatories, and they are therefore accessible to all who can consult any of the great libraries; but the collection of these into one volume is a great convenience.

Quite a number of the cuts, however, must have been copied from photographs privately distributed, which, of course, are not generally accessible, nor widely known, and for the reproduction of these we cannot be too grateful. We may instance the extremely interesting cut of Mr. Newall's great telescope of 25 inches aperture (made by Cooke, of York), which was the largest refractor in the world until the mounting of the Clark telescope at the United States Naval Observatory at Washington, in 1873.

A propos of large telescopes, the authors tell us that the two large disks of glass (30 inches in diameter) which have been in the possession of the Paris Observatory since 1855, are shortly to be ground into lenses and mounted, so that, provided the operation of grinding is successful, and no unknown flaws in the glass exist, Paris will soon have a larger equatorial than any now mounted.

Americans, however, may console themselves with the thought that the magnificent gift of Mr. Lick, of San Francisco ($700,000), will soon become available "to construct a more powerful telescope than any now in the world," and they may safely trust to the artistic skill and to the scientific sagacity of the Clarks, to whom the work will undoubtedly be confided, to make the most perfect instrument yet known.

The book treats largely, too, of the history of the private observatories of England, and it is no small convenience to have gathered into one volume material which, if in print at all, is scattered through many volumes of rare periodicals and books.

In this volume 50 pages are devoted to the Observatory of Greenwich alone, and then follow accounts of those observatories which belong to universities, to learned societies, or to cities; and, finally, 80 pages are concerned with the observatories of private gentlemen.

It will be seen that this is a very full account, and we may say that, besides being a book of great interest to the astronomer, it will be highly interesting to the general reader who is anxious to be informed about this important subject.

We notice very few omissions: the most striking one, however, is the absence of any account of the Bedford Observatory, of Admiral Smyth, which should be notable if only as the birthplace of the "Bedford Catalogue," one of the most curious of astronomical publications.

Perhaps the omission of the celebrated catalogue of "Double Stars" from among the works of Mr. Dawes, the noted observer of double stars, might also be mentioned.

But these are minor points, and do not prevent the book from being a perfect success, creditable to its authors, and a valuable contribution to the literature of astronomy.

We look forward with eagerness to the appearance of the remaining two volumes.

It is to be hoped that the book, or at least that part of it which refers to the observatories in the United States, may be translated into English, for the use and information of many Americans who will not see the original French edition.

Since Loomis's "Recent Progress of Astronomy in the United States," nothing of importance has been published here, on this subject, if we except two papers on observatories in the United States, which have recently appeared in Harper s Magazine.

There undoubtedly exists among Americans a very strong interest in astronomy generally and in the doings of observatories, and a greater knowledge of the many institutions of this kind in the United States would undoubtedly lead to more intelligent and concerted action on the part of the private gentlemen who own them.

For example, if a person who has a fine meridian instrument knows that the Harvard-College Observatory is observing a certain zone of stars, he will not commit the folly of wasting his time and his labor by doing the same work, but will rather turn his attention to something which is yet undone. To know what is yet undone is often the question, and this book supplies in a measure the want, for it tells us what is doing.

Perhaps this is as good a place as any to call the attention of amateur astronomers to the important work which they may do, if they will only choose some special subject, make themselves familiar with what has been done in it, and then devote even a small portion of time to its regular and systematic pursuit.

Numerous examples of such valuable work done by amateurs are to be found in the book before us: and in many cases this work was done by gentlemen who were not able to devote their whole time, or any thing like it, to astronomy.

Dawes, the great double-star observer; Carrington, the assiduous observer of circumpolar stars, and of solar spots; Lassell, the great physical astronomer; with De La Rue, Huggins, Lockyer, and others, have done permanent good to science, and have acquired great reputation, while most of them followed other pursuits.

And we may hope that such knowledge as is attainable from this book will induce American amateurs to limit themselves to some useful but special inquiry in which they may gain credit, and render useful service to astronomy.E. A. H.

The Journal of Speculative Philosophy, July, 1874. Quarterly, whole number 31. Price 50 cts. a number, or $2 a year. Edited and published by William T. Harris, St. Louis, Mo.

This periodical, which has come to be recognized as the organ of speculative thought in this country, has now reached its eighth volume, and the series forms a philosophical library of great value to metaphysical students who keep up their interest in abstract and abstruse inquiries. It is the policy of the editor to make his periodical not so much a vehicle of contemporary speculation as a summary of the doctrines and expositions of the greatest philosophical thinkers of past times. Accordingly, the published volumes will be found largely occupied by essays and discussions from the writings of such men as Leibnitz, Descartes, Kant, Fichte, Schelling, Hegel, Goethe, Rosenkrantz, Schopenhauer, Hartmann, Herder, Trendelenburg, and others. From such writers we have in the pages of this magazine an authoritative and all-sided presentation of metaphysical questions, such as can be otherwise obtained only by ransacking extensive libraries. An important feature of the magazine is the considerable space it devotes to the criticism and interpretation of the works of art, poetic, dramatic, musical, pictorial, architectural, etc.

The first article of the July number of this magazine is an addition to the voluminous literature of Shakespearean criticism, by D. J. Snider. In an acute and ingenious analysis of "The Tempest" the author aims to show that this drama is a profound philosophical study of two worlds, the real and the ideal. As it is latterly the fashion for lawyers, doctors, and scientists, to find every thing in Shakespeare as fast as it is discovered elsewhere, so the present writer would seem to assume that the poet had anticipated the last results of German metaphysics. Will not this vein at length give out? Daniel Wilson has lately been over the same ground, and devoted a solid volume to prove that in "The Tempest" Shakespeare has anticipated the modern doctrine of Evolution. Among the questions debated by the schoolmen of the middle ages, the following is reported: "Was Adam, while yet without sin, acquainted with the 'Liber Sententiarum' of Peter Lombardus, Bishop of Paris?" It would seem to be an open question with many of our later commentators and schoolmen, whether Shakespeare may not really have been acquainted with the works of Darwin and Hegel! "The Music of Color," the second article, is an ingenious and instructive statement of the analogies of light and sound as explicable on the wave-theory. Many efforts have been before made to find harmonic relations between the spectrum and the gamut, but the results have been regarded as unsatisfactory. The present writer presses the analogy in many particulars, and is confident that it will ultimately be fully established. In the third article Prof. Vera treats of "Ideas as the Essences of Things." He takes the high Platonic ground of independent and eternal ideals, saying: "The force that produces the plant, and according to which the plant grows and dies, is its idea. The real and absolute germ is not the individual and external germ we touch and see, but the idea by which the external germ is created and endowed with the necessary force for its growth and preservation." "Thoughts on the Intellect" is a translation from one of the powerful works of Schopenhauer, in which that pestilent old pessimist puts the entire philosophy of things in the following nut-shell: "The laws and powers of Nature, together with matter in which they inhere, constitute here the given, and consequently the absolute real, taken generally; but regarded specially, as innumerable suns and planets, floating in infinite space. These are therefore, as the result, everywhere, nothing but balls, a part of which are shining, the rest illuminated. Upon the last, life has unfolded itself in consequence of a process of putrefaction, which, in gradual succession, produces temporary organic beings, rising and perishing through generation and death according to the laws of Nature governing the power of life, which, like all the others, make up the reigning (and from eternity to eternity) existing order of things, without beginning or end, and without giving account of themselves. The highest point of this succession is occupied by man, whose existence also has a beginning, in its course many and great miseries, few and parsimoniously-granted joys, and after this, like every thing, has an end; after which, it is as if it never had been."

Mr. Stephen Pearl Andrews contributes a paper on the "Revisal of Kant's Categories." He is the author, as is well known, of an elaborate philosophical system which he denominates "Universology," and one of the features of which is a universal language. Mr. Andrews is a philosophical linguist, and his studies have brought him to the conclusion that there can be no comprehensive and perfected system of philosophic thought that does not include some means of systematic security against the errors which arise from the defects of language and the multiplicity of tongues. In the present paper he takes the "categories" arrived at by the transcendental analysis of Kant, and seeks for those elements and conditions of the structure of language which correspond to these categories. He says: "The three categories of quantity are Unity, Manifoldness, and Universality, which are no more than the same ideas which, in respect to grammar, we indicate by the terms 'singular, plural, and common.'" He then proceeds to trace out other analogies or correspondences, and shows that grammar throughout has its true basis in logic.

The number before us of the Journal of Speculative Philosophy contains other articles, as an analysis of the music of "Robert Schumann," Herbart's "Rational Psychology," and various minor discussions, but the essays noticed will give an idea of the scope and variety of the subjects treated in its pages. If it be thought that this magazine is too sublimated in its speculations for practical service in this age, we must remember that the age needs improving; that the tendency of all science is toward the establishment of generalizations or abstract principles; and we must not forget that this journal is edited by one of the most able and thorough of the practical educators of the country.

This pamphlet of 92 large pages, double columns and in small type, contains an immense amount of miscellaneous scientific information boiled down to a state of concentration that is only equaled by the cheapness for which the whole is sold. There are nearly 150 articles, many of them quite full, some of them illustrated, and all of them on the latest aspects, results, and tendencies of contemporary science. In its series of cheap scientific publications, freighted with useful information for the people, the Tribune is doing an important work of popular education, and deserves to be widely and liberally sustained.

Exposures in Fire-insurance. By William Frazier Ross. New York: D. Appleton & Co.

In the language of fire-insurance, all insurable property is subject to certain exposures or liabilities to take fire. For instance, a building so situated in relation to a storehouse of oils or spirits, that, were the liquids to take fire, they would flow toward it, is therein subject to an exposure. Exposures are numerous and varied in kind, and upon the number and quality of those to which a building is subjected does its rate of premium depend. This makes apparent the necessity for a reliable method of estimating the exposures. The difficulty hitherto in the way has been want of statistics, and this deficiency it is the object of this little volume to supply. In the main, it fulfills its purpose, but the habitual use of technical terms, without explanation of their meaning, and the occasional occurrence in close proximity of a word, first in its technical and then in its common acceptation, is calculated to confuse the general reader. By its use, property-holders will be enabled to estimate for themselves the cost of insuring their property, and thus to establish a check on over-charges.

An Introduction to the Study of General Biology. By Thomas C. MacGinley. New York: G. P. Putnam's Sons. 198 pages. Price, 75 cents.

This is an ambitious attempt to supply what is still needed—a good text-book on biology for schools. The author deals extensively with the torula, or yeast-plant, bacterium, protococcus, and other low forms of life, and gives but a single example of the three highest branches. In this respect the subject-matter of the book is not properly balanced. While there is much to commend, there is much to object to in the obscure and shocking character of many of the figures, as being more likely to mislead than to aid. Many of them look faithful copies of hasty and crude pencil-notes of hasty and crude drawings made on the black-board.

Statistical Atlas of the United States. Part II. Population, Social and Industrial Statistics.

This is part of a series of large folio maps intended to represent, graphically, first the progress of the United States, both as regards acquisition of territory and increase of population, and then the relative proportions of the various race-elements. To the illustration of these subjects are devoted sixteen sheets of the atlas. The remaining eleven sheets represent the ratio to total population of illiteracy, of church accommodation, of producers, etc., and the distribution of wealth, public indebtedness, taxation, revenue, expenditures, and agricultural products.

This timely little volume was contributed in installments to Nature, and these are now collected and issued in the neat form of Macmillan's "Nature Series." It gives an interesting account of the general subject, first, in its historical aspect; second, the scientific conditions of the problem; third, the preparations for solving it by the different nations. The volume is copiously illustrated, and will meet the wants of general readers who wish to know something about the great scientific event that is to happen in December. At the close of the third chapter, the author thus recapitulates the technical view of the subject:

"1. We know the relative dimensions of the solar system accurately; but we do not know the scale.

"2. The determination of the distance of the earth from the sun, or from any of the planets, at a fixed date, fixes the scale.

"3. This may be determined (1) by the aid of a transit of Venus; (2) by an opposition of Mais; (3) by a knowledge of the velocity of light, combined with observations of eclipses of Jupiter's satellites; (4) by the velocity of light and the constant of aberration; (5) by the calculated effects of the sun's disturbance upon the lunar motions.

"4. A transit of Venus may be utilized:

"(a.) By the determination of times of contact at different stations, combined with a knowledge of the longitudes of these stations.

"(b.) By determining the least distance between the centres of the sun and Venus during the transit, observed from different stations.

"5. This last determination may be made by any of these methods:

"(1.) The photographic method.

"(2.) The heliometric method.

"(3.) The method of durations."

A Work of Great Importance.—The twelfth volume of the " International Scientific Series" is contributed by Dr. John W. Draper, and will be a " History of the Conflict between Religion and Science." It might seem strange that such a history has never been written before, but the subject has had to wait for the historian. It is doubtful if there is another man living besides Dr. Draper who has had the peculiar preparation necessary for executing so difficult a task. Dr. Draper's familiarity with science is extensive. He has cultivated large tracts of it as an original investigator, and with a success that has given him a world-wide reputation. He has also been a life-long student of history, and has considered his questions largely from his point of view as a student of Nature. Dr. Draper's " History of the Intellectual Development of Europe " is one of the great books of this age; and that it is so appreciated is shown by the fact that it has been translated into nearly all the languages of Europe. The study of the problem of the intellectual development of man which has taken place in Europe in historic times, was a grand preparation for treating the special relations of religion and science in their historic aspects. The volume is written in a remarkably clear and attractive style, suitable for all readers, and it abounds in fresh and striking views, vividly and boldly presented. Dr. Draper's book is certain to make a profound impression upon the public mind.

In the Preface to this complete edition of his Address, Prof. Tyndall says that it was written in the Alps, and was sent home in installments to be printed; but, being too long for oral delivery, he was compelled to omit certain parts, while only what he read was given to the public. The omitted passages are now supplied, the whole has been thoroughly revised, and a Preface is added in which the Professor pays his respects to some of his detractors. Regarding one of these imputations, he says: " In connection with the charge of atheism, I would make one remark. Christian men are proved by their writings to have their hour of weakness and of doubt, as well as their hours of strength and of conviction; and men like myself share, in their own way, these variations of mood and tense. Were the religious views of many of my assailants the only alternative ones, I do not know how strong the claims of the doctrine of 'material atheism' upon my allegiance might be. Probably they would be very strong. But, as it is, I have noticed, during years of self-observation, that it is not in hours of clearness and vigor that this doctrine commends itself to my mind; that in the presence of stronger and healthier thought it ever dissolves and disappears, as offering no solution of the mystery in which we dwell, and of which we form a part."